Genotoxicity test of vulcanized rubber and residual chemicals used in curing processes using reverse mutation assay of Salmonella typhimurium

Abstract

Reverse mutation assay of Salmonella typhimurium strain TA98 and TA100 was used for determination of genotoxic effect of 13 chemicals used in rubber industry and vulcanization as accellerator, activator, antioxidant, filler and vulcanizing agent. Three chemicals in the accellerator group were found genotoxic for strain TA98 namely zinc dibutyl dithiocarbamate (ZBEC), zinc dibuthyldithiocarbamate (ZDBC), mercapto benzothiazole (MBTS) at the concentration 100 microgram/plate. ZDBC exhibited indirect genotoxic effect in the presence of metabolic activation by enzyme from rat liver, but ZBEC and MBTS exhibited the direct genotoxic, therefore the genotoxic potential of the chemical use as accelerator were ranked from high to low as the following. : ZBEC>MBTS>ZDBC>DPTT>ZMBT. Besides, the result indicate that butyl hydroxytoluene (BHT) used as antioxidant and sulfur are cytotoxic to bacterial cells. How ever when vulcanizates were prepared from 6 formulations by using sulfur, peroxide and radiation vulcanization system and extracting residual chemicals by toluene and chloroform:methanol (1:1), none of the rubber vulcanizate show genotoxic effect under this testing condition. The number of mutant colonies when extract by chloroform:methanol(1:1) were more than toluene but less than double of negative control. The result indicate that sulfur curing system was not suitable to produce medical device, because many chemicals were added that may be genotoxic and cytotoxic and therefore more risk than peroxide and rediation curing systems